<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>事件委托</title>
</head>
<body>
<ul>
    <li>1</li>
    <li>2</li>
    <li>3</li>
    <li>4</li>
    <li>5</li>
</ul>

<!--那个v是个对象，-->
<script>
    document.getElementsByTagName("ul")[0].addEventListener("click",function (v) {
        if(v.target.innerHTML == 3){
            console.log("传的参数是当前点击的对象");
        }
    });
</script>
</body>
</html>